A geometric approach to establishment of datum reference frames

A datum reference frame is a coordinate system used to locate and orient port features. Constructing a datum reference frame from a set of features is a complicated process involving: 1) specifying a valid combination and the precedence of the datum features which define the datum reference frame; 2) developing from datum features of the part; and 3) determining the position and orientation of the datum reference frame from the data. In this paper, we develop a geometric theory for establishing datum reference frames, and present a sequential procedure that transforms the primary, secondary and tertiary datum problems as a minimization or a constrained minimization problem. We develop simple algorithms to solve these problems, and give simulation results illustrating efficiency and simplicity of the approach.